Localization of aquaporin-2, renal morphology and urine composition in the bottlenose dolphin and the Baird’s beaked whale

Suzuki, Miwa; Endo, Naoko; Nakano, Yuichi; Kato, Haruhiko; Kishiro, Toshiya; Asahina, Kiyoshi

doi:10.1007/s00360-007-0204-1

Cited by 17 publications

(16 citation statements)

References 34 publications

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“…9). 26,32,38,39 Glutathione S-transferase-a GST-a had variable expression within the dog kidney. Interestingly, the transitional epithelium lining the renal papilla of some dogs was positive for GST-a staining along the cell borders and diffusely throughout the nucleus (Fig.…”

Section: Aquaporinmentioning

confidence: 99%

Localization of Canine, Feline, and Mouse Renal Membrane Proteins

et al. 2011

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Immunohistochemistry allows the localization of proteins to specific regions of the nephron. This article reports the identification and localization of proteins in situ within normal canine, feline, and mouse kidney by immunohistochemistry; maps their distribution; and compares results to previously reported findings in other species. The proteins investigated are aquaporin 1, aquaporin 2, calbindin D-28k, glutathione S-transferase-a, and Tamm-Horsfall protein. Aquaporins are integral membrane proteins involved in water transport across cell membranes. Calbindin D-28k is involved in renal calcium metabolism. Glutathione S-transferase-a is a protein that aids in detoxification and drug metabolism. The role of Tamm-Horsfall protein is not fully understood. Proposed functions include inhibition of calcium crystallization and reduction of bacterial urinary tract infection. The authors' findings in the dog are similar to those in other species: Specifically, the authors localize aquaporin 1 to the proximal convoluted tubule epithelium, vasa recta endothelium, and descending thin limbs; aquaporin 2 to collecting duct epithelium; and calbindin D-28k within distal convoluted tubule epithelium. Glutathione S-transferase-a has variable expression and is found in only the renal transitional epithelium in some individuals, in only the proximal straight tubules in others, or in both locations in others. Tamm-Horsfall protein localizes to thick ascending limb epithelium. These findings are similar in the cat, with the exception that aquaporin 1 is located in glomerular podocytes, in addition to proximal convoluted tubule epithelium, and glutathione S-transferase-a is found solely within the proximal convoluted tubule within all kidney samples examined. The mouse kidney is almost identical to the dog but expresses glutathione S-transferase-a in the glomeruli only.Keywords aquaporin, calbindin, canine, feline, glutathione S-transferase-a, immunohistochemistry, kidney, mouse, Tamm Horsfall protein Immunohistochemistry (IHC) utilizing aquaporin 1 (AQP1), aquaporin 2 (AQP2), glutathione S-transferase-a (GST-a), calbindin D-28k, and Tamm-Horsfall protein (THP) antibodies has been used to localize these proteins to segments of the nephron in various species, including human and rat kidneys. 6,13,19,23,[25][26][27]30,39,40 Identification of specific segments of the nephron can be challenging histologically. AQP1, AQP2, THP, and calbindin D-28k have been used as nephron segment markers and utilized in double-labeling IHC to more exactly localize other proteins within the nephron of humans and rats.21 By localizing proteins of interest within the nephron, we can further elucidate the function of these proteins in renal physiology and pathophysiology and may be better able to identify nephron segments in disease states.Our study establishes the in situ location of proteins that have a distribution well documented in other species and identifies these proteins as nephron segment markers in the dog, cat, and mouse kidney. The pro...

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Section: Aquaporinmentioning

confidence: 99%

Localization of Canine, Feline, and Mouse Renal Membrane Proteins

et al. 2011

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“…The concentrations of corresponding constituents in the urine of fin whales and bottlenose dolphins were obtained from literature (Kjeld 2001;Suzuki et al 2008) and compared with those of the freshwater and marine finless porpoise.…”

Section: Blood and Urine Analysismentioning

confidence: 99%

Concentrations of osmotically related constituents in plasma and urine of finless porpoise (Neophocaena asiaeorientalis): implications for osmoregulatory strategies for marine mammals living in freshwater

et al. 2014

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Background: Most cetaceans inhabit the hyperosmotic marine environment with only a few species living in freshwater habitats. The Yangtze finless porpoise (Neophocaena asiaeorientalis asiaeorientalis) is the only freshwater subspecies of the genus. Our aim was to study whether the osmoregulation mechanism of the Yangtze finless porpoise is different from the marine subspecies, the East Asian finless porpoise (Neophocaena asiaeorientalis sunameri). We assayed and compared the concentrations of the constituents involved in osmoregulation in the blood and urine in the Yangtze finless porpoise and the East Asian finless porpoise. We also compared the corresponding urine constituents of the porpoises with existing data on fin whales (Balaenoptera physalus) and bottlenose dolphins (Tursiops truncatus). Results: The mean plasma osmolality of Yangtze finless porpoise was significantly lower than that of the marine subspecies (P < 0.01). Similarly, the urine osmolality of Yangtze finless porpoise was also significantly lower than that of its marine counterpart (P < 0.05). However, the urine sodium concentration of freshwater finless porpoise was significantly lower than that in the marine subspecies (P < 0.01), even though their serum sodium has no significant difference. Moreover, the freshwater porpoise has significantly lower urine urea concentration but much higher serum urea than in the marine finless porpoise (P < 0.05). Conclusions: These results suggest that the freshwater finless porpoise does have different osmoregulatory mechanism from marine cetaceans. Conserving sodium by excreting urine with low ion levels may be an essential strategy to maintain the serum electrolyte balance for the freshwater subspecies that also appears to be more susceptible to hyponatremia.

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“…It was previously reported that AQP2 is distributed in the principal cells of the kidneys of the bottlenose dolphin and Baird's beaked whale, similar to terrestrial mammals (Suzuki et al, 2008). During the process of the present study, unique data were unexpectedly obtained from rapid amplification of cDNA ends (RACE)-PCR experiments, indicating alternative splicing of the AQP2 gene expressed in many organs of bottlenose dolphin.…”

Section: Introductionmentioning

confidence: 70%

“…Immunohistochemical localization of AQP2 and alternative AQP2 in the kidney of the dolphin was determined using the method previously described (Suzuki et al, 2008). Alternative AQP2 distribution was also detected in another 15 organs (epidermis, esophagus, forestomach, main stomach, pyloric stomach, small intestine, liver, pancreas, spleen, adrenal gland, ovary, lung, muscle, heart and brain).…”

Section: Immunohistochemistry and Immunoblottingmentioning

confidence: 99%

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Two isoforms of aquaporin 2 responsive to hypertonic stress in bottlenose dolphin

Suzuki

Wakui

Itou

et al. 2016

Journal of Experimental Biology

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This study investigated the expression of aquaporin 2 (AQP2) and its newly found alternatively spliced isoform (alternative AQP2) and the functions of these AQP2 isoforms in the cellular hyperosmotic tolerance in the bottlenose dolphin, Tursiops truncatus. mRNA sequencing revealed that alternative AQP2 lacks the fourth exon and instead has a longer third exon that includes a part of the original third intron. The portion of the third intron, now part of the coding region of alternative AQP2, is highly conserved among many species of the order Cetacea but not among terrestrial mammals. Semiquantitative PCR revealed that AQP2 was expressed only in the kidney, similar to terrestrial mammals. In contrast, alternative AQP2 was expressed in all organs examined, with strong expression in the kidney. In cultured renal cells, expression of both AQP2 isoforms was upregulated by the addition to the medium of NaCl but not by the addition of mannitol, indicating that the expression of both isoforms is induced by hypersalinity. Treatment with small interfering RNA for both isoforms resulted in a decrease in cell viability in hypertonic medium (500 mOsm kg ) when compared with controls. These findings indicate that the expression of alternatively spliced AQP2 is ubiquitous in cetacean species, and it may be one of the molecules important for cellular osmotic tolerance throughout the body.

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Localization of aquaporin-2, renal morphology and urine composition in the bottlenose dolphin and the Baird’s beaked whale

Cited by 17 publications

References 34 publications

Localization of Canine, Feline, and Mouse Renal Membrane Proteins

Localization of Canine, Feline, and Mouse Renal Membrane Proteins

Concentrations of osmotically related constituents in plasma and urine of finless porpoise (Neophocaena asiaeorientalis): implications for osmoregulatory strategies for marine mammals living in freshwater

Two isoforms of aquaporin 2 responsive to hypertonic stress in bottlenose dolphin

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